1. Field of the Invention
The invention relates to a winch mechanism having a first winch with a first winch drum driven in rotary manner by a first drive via a first gear, a second winch with a second winch drum driven in rotary manner by a second drive via a second gear, and a synchronizing device making it possible to synchronous a rotation of the first winch drum with a rotation of the second winch drum.
2. Related Art
Such double winch mechanisms with two winch drums and two separate drives are more particularly used for cranes and other lifting devices. A force distribution over at least two cables is advantageous for strength and safety reasons. Production and cost advantages result from the use of two smaller drives in place of one large drive. The use of two winch drums basically permits a joint and a separate operation of the cables, so that high functionality results from such a winch mechanism.
Such a winch mechanism can e.g. be gathered from JP 52147849 A. The two winch drums are in each case driven by a hydraulic motor. The two hydraulic motors can be synchronized by a corresponding hydraulic connection. However, even minor leaks in the hydraulic system can impair synchronization.
AT 309 011 B discloses a device for controlling the synchronism of at least two motor-moved winches, synchronization being brought about by a relay connection. However, due to their sensitivity, electrical and electronic components can lead to malfunctions, e.g. when used in construction machines under rough construction site conditions.
A gear for driving two drum winches can be gathered from DE 37 10 132 C2. In this case the two winch drums are driven by means of a common main driving motor, so that necessarily synchronization takes place. A differentiated drive of the two drums can be achieved using a positioning motor via a corresponding gear adjustment.